Brake lights and wiring

The original rear brake light/signal wiring was very damaged with age.  As was the back end of the intermediate wiring harness.  I rewired the rear harness and repaired the intermediate harness using the appropriate color replacement wiring of course.

Intermediate brake harness repaired. Click to enlarge – use browser back button to return.
Rear brake/taillight harness. Click to enlarge – use browser back button to return.
New GXL wire for harness replacement. Click to enlarge – use browser back button to return.

Lights!!  Brakes and taillights!

2 Replies to “Brake lights and wiring”

  1. I’m just about to start this process. Really appreciate all the work you’ve done and shared here. Can you tell me – did you need to 1966 Supplement Manual to figure out the wiring?

    We bought a ’66 with a Vortec engine – we think it’s 4.8 or 5.3, but none of the gauges from the original dash are working and I’d like to hook them up. Not sure if I need to get a wiring harness special for this? My husband got the gas gauge on the cluster working after replacing the broken float mechanism in the gas tank.

    I’m wondering if we can figure out the wiring for the guages to the old gauge cluster on our own. What would you suggest? Thanks again!

    1. Thanks. I have the Supplemental Manual, but never really used it much. Wiring was pretty simple in these old trucks. Most of the wire colors are the same across all the GM models. As for the original gauges, you can use the original sending units for each. You just need to adapt them to the newer motor which has metric threads. The speedo may be a special connection if you have a newer transmission. Original uses a speedometer cable and newer transmissions are electronic. You can purchase an adapter for this also, but they are expensive. I have several OEM wiring diagrams on this site if you need them.

      Also see

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